Current indications for ophtalmalic intravitreal injections may include: diabetic retinopathy; macular degeneration; ocular infection; retinal swelling; retinal vascular disease, and choroidal neovascular membrane. Intravitreal injection may provide a route of administration of a drug, such as an anesthetic, to the posterior segment of the eye where the drug may reach the retina and sub retinal tissues in higher concentrations than topical or systemic administration may provide.
The injection may be a pars plana injection into the vitreous cavity (intravitreal). The pars plana refers to an internal structure of the eyewall between ciliary body and the retina. It is particularly desirable not to inject through the retina, as this may put a hole in the retina, possibly leading to a retinal detachment. However, if the injection site is too close to the limbus damage to the lens of the eye by the needle may be likely to occur. Therefore, it is desirable that the injection penetrate the pars plana. Since the pars plana may not be directly visualized during the injection, it is desirable that a visible mark be made on the sclera (white part of the eye) prior to the injection. The mark may indicate the location of the underlying pars plana.
Use of a scleral marker is desirable for intravitreal injection because there may be a very narrow range for the injection site. The scleral marker may be used to measure a very precise distance and mark it on the sclera where it may be visible to the physician. Scleral markers typically have a pair of opposite ends, with each end forked to define two points a desired distance depending upon the intended usage. For use in procedures involving adult human eyes, one end has points spaced 3.5 mm apart and the other end has points spaced 4 mm apart. The physician selects which spacing is appropriate for a given patent and procedure. The desired spacings will typically be different for other applications, such as pediatric or for veterinary uses. Thus, specific spacing markers are produced for a given area of practice.
During use of a scleral marker by a surgeon in marking the eye for injection, one point of the marker may be placed at the limbus of the eye and the other point may be pressed in to the sclera of the eye, making an indentation to mark the injection site. Alternatively, a sterile marking pen may be used to apply ink to one of the marker points which may then be transferred to the sclera when the point is placed against the eye wall. Some physicians may make an indentation with the caliper and then highlight that indentation with the sterile marker.
Autoclave or radiation sterilization may typically be employed to sterilize a re-usable marker. Most physicians may perform multiple (>30) injections per day. The sterilization process takes too long to efficiently re-sterilize the instruments between patients. Therefore, multiple, costly, re-usable markers may be purchased to use throughout the day and then sterilized together at the end of the day. Most intravitreal injections are performed outside the operating room in a physician's office. Many offices do not have access to sterilization machinery and therefore the used markers may have to be sent out for sterilization before re-use. If the office does have sterilization equipment, a great deal of staff time may be required for sterilization.
For this reason, disposable or single use plastic scleral markers have become increasingly popular. Typically, a sterile marker is provided in sealed sterilized packaging alone or in combination with other surgical instruments for a procedure, such as a speculum. However, it has been observed that the fine points of the scleral marker may become damaged in the packaging or else penetrate the packaging and compromise the sterile conditions. The disclosure relates to a single use scleral marker configured to protect the points to overcome the disadvantages of conventional single use scleral markers.